python: Drop ${PYTHON_PN}

python 2 is gone and we don't need the abstraction now, drop the remaining usage
of this variable.

The definition in python3-dir.bbclass is left for now for other layers.

(From OE-Core rev: b566b1e32c7993d1ab7795562f648e52ce186a70)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3-ndg-httpsclient_0.5.1.bb

@@ -11,15 +11,15 @@ inherit pypi setuptools3 update-alternatives
 PYPI_PACKAGE = "ndg_httpsclient"
 
 DEPENDS += " \
-    ${PYTHON_PN}-pyopenssl \
-    ${PYTHON_PN}-pyasn1 \
+    python3-pyopenssl \
+    python3-pyasn1 \
 "
 
 RDEPENDS:${PN} += " \
-    ${PYTHON_PN}-datetime \
-    ${PYTHON_PN}-logging \
-    ${PYTHON_PN}-pyopenssl \
-    ${PYTHON_PN}-pyasn1 \
+    python3-datetime \
+    python3-logging \
+    python3-pyopenssl \
+    python3-pyasn1 \
 "
 
 BBCLASSEXTEND = "native nativesdk"